Travis: Remove make.py test for events and littlefs

[hugueskamba]

Summary of changes

Fixes #14139

The removed tests were building applications from the content of their
respective README files. The events test was building with the full profile twice.
The first time with the repository as is; and the second time after deleting
some directories (to simulate the baremetal profile).
The littlefs test was building once with the full profile.

Testing make.py is no longer required as it is no longer supported.
There is already test coverage for APIs in the removed tests.

Impact of changes

Migration actions required

Documentation

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Pull request type

[x] Patch update (Bug fix / Target update / Docs update / Test update / Refactor)
[] Feature update (New feature / Functionality change / New API)
[] Major update (Breaking change E.g. Return code change / API behaviour change)

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Test results

[] No Tests required for this change (E.g docs only update)
[x] Covered by existing mbed-os tests (Greentea or Unittest)
[] Tests / results supplied as part of this PR

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Reviewers

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[ciarmcom]

@hugueskamba, thank you for your changes.
@ARMmbed/mbed-os-maintainers please review.

[0xc0170]

should we also remove littlefs - a question is why littlefs is part of travis and not other components as well? Lets check the tests and the CI and remove it

[hugueskamba]

should we also remove littlefs - a question is why littlefs is part of travis and not other components as well? Lets check the tests and the CI and remove it

That IMO is another conversation to have independently of this PR.